Manual controls, such as joysticks, are well known. Joysticks, for example both movable and isometric, provide positioning data for either incremental or variable rate positioning. Other manual controls include track balls, cursor control keys, data tablets, light pens, and "the mouse". While these control devices have been well used, each has problems such as hysteresis ("jumping" in the final approach to the target); nonhomogeneity of movement, especially noticeable near the limits of the control field; a requirement for excessive space such as that required by the "mouse"; and a dependence upon initial cursor position required by fixed rate and variable rate joysticks and the "mouse". The noted control elements also do not provide for consonance with the hand anatomy, that is, with the natural rotational movements associated with controlling the motions of an individual's wrist and arm motion.
Some workers in the field have attempted to solve the various positioning problems. For example, one worker adapts a multiple ratio control element which increments to a controlled position at a varying ratio to the increment in controller position depending upon the rate of movement of the manual control. This addresses the hysteresis problem but allows no "fixed mapping" of the control element position to the controlled position. Thus, this prior art method depends upon the initial starting position of the control element for incremental movement control.
It is therefore a primary object of the invention to provide a manual control apparatus and method adapted, substantially, to the natural movement of the hand to control movement of a position indicating element in two dimensions and which can be employed continuously without substantial fatigue. Other objects of the invention are a control apparatus which is simple and inexpensive to build and which is reliable and easy to operate. A further object of the invention is a position control apparatus and method wherein the indicated position of the control element translates, on a one-to-one basis, to the end position of a position indicating element.